Chlorido[N′-(2-oxidobenzilidene)acetohydrazide-κ2 O,N′,O′]copper(II) dihydrate

In the title complex, [Cu(C9H9N2O2)Cl]·2H2O, prepared from the Schiff base ligand N′-(2-hydroxybenzilidene)acetohydrazide and copper(II) chloride, the CuII atom is coordinated by two O atoms and one N atom from the ligand and by a Cl atom in a distorted square-planar geometry. The two donor O atoms of the tridentate Schiff base ligand are in a trans arrangement. In the crystal structure, there is an extensive intermolecular hydrogen-bonding network; N—H⋯O, O—H⋯O and O—H⋯Cl interactions, involving the uncoordinated water molecules, lead to the formation of a two-dimensional network parallel to the ab plane.

In the title complex, [Cu(C 9 H 9 N 2 O 2 )Cl]Á2H 2 O, prepared from the Schiff base ligand N 0 -(2-hydroxybenzilidene)acetohydrazide and copper(II) chloride, the Cu II atom is coordinated by two O atoms and one N atom from the ligand and by a Cl atom in a distorted square-planar geometry. The two donor O atoms of the tridentate Schiff base ligand are in a trans arrangement. In the crystal structure, there is an extensive intermolecular hydrogen-bonding network; N-HÁ Á ÁO, O-HÁ Á ÁO and O-HÁ Á ÁCl interactions, involving the uncoordinated water molecules, lead to the formation of a two-dimensional network parallel to the ab plane.

Comment
The title complex, (I), was prepared by the reaction of the Schiff base ligand N'-(2-hydroxybenzilidene)acetohydrazide with copper(II) chloride. The molecular structure of (I) is illustrated in Fig. 1, and selected bond distances and angles are given in Table 1. Atom Cu1 is coordinated to two O-atoms and one N-atom from the Schiff base ligand and to one chloride atom. The Cu1-N and Cu1-O bond distances are similar to those observed in other Cu II complexes of the same and similar tridentate ligands (Ainscough et al., 1998;Chan et al., 1995;Koh et al., 1998). The Cu1-Cl distance (2.2203 (5) Å) is similar to that observed in other copper(II) square-planar complexes (Li et al., 2008;Qiu & Wu, 2004). The two O donor atoms are in a trans arrangement with a O-Cu1-O angle of 170.21 (6)°. The angles around atom Cu1 are in the range of 81.39 (6) -173.31 (5)°. The sum of the angles around atom Cu1 is 360.46°, suggesting that the geometry around the copper atom is distorted square-planar.
In the crystal structure of (I) there is an extensive intermolecular hydrogen bonding network (Fig. 2). N-H···O, O-H···O and O-H···Cl interactions (Table 2), involving the lattice water molecules, lead to the formation of a two-dimensional network parallel to the ab plane.

Refinement
The NH hydrogen atom was located in a difference Fourier map and freely refined: 0.81 (3) Fig. 1. A view of the molecular structure of compound (I), showing the atom-numbering scheme. Displacement ellipsoids are drawn at the 50% probability level.  Table 2 for details).

sup-2 Figures
Crystal data [Cu(C 9   Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.